Manhole-cover



(No Model.)

C. P. BINGHAM. MANHOLE COVER.

INVENTOR.

WITNESSES.

ATTORNEYS.

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" NiTED STATES CHARLES F. BINGHAM, OF BUFFALO, NEW YORK.

MAN HOLE-COVER.

SPECIFICATION forming part of Letters Patent No. 576,253, dated February 2, 1897.

Application led April 8, 1895. Serial No. 544,884. (No model.) 'Y

To all whom t 71mg concern:

Be it known that I, CHARLES F. BINGHAM, a citizen of the United States, residing at Buf falo, in the county of Erie and State of New York, have invented a new and useful Im provement in Manhole-Covers, of which the following is a specification.

This invention relates to a manhole cover or casing which is especially desirable for electric-wire conduits, although the same is also useful in connection with sewers.

My invention has for its object to provide the manholecasing with means which permits the free escape of any gases that may accumulate in the manhole, but which at the same time excludes the atmosphere from the manhole, the presence of damp air in the manhole being objectionable because of its conductive property.

In the accompanying drawings, Figure l is a sectional elevation of my improved man hole cover or casing in connection with an electricwire conduit. Fig. 2 is a top plan view thereof. Fig. 3 is a horizontal section of the same in line 3 3, Fig. l.

Like letters of reference refer to like parts in the several figures.

A represents the manhole proper, and B conduits opening into the same.

O is the manhole casingor cover, which may be of circular 0r other suitable form, and which rests upon the briekivork forming The walls of the manhole.

D is the removable lid or cover of the casing, which is seated upon a rabbet formed at the upper end of the casing, so as to be iiush with the top of the latter. This cover is formed with a Ventilating or gas-escape opening d, which is preferably ilared downward to prevent dirt from lodging therein, and which is surrounded on the upper sides of the cover by a sloping rim d', which sheds Water from the opening.

E is a horizontal diaphragln or dirt-trap arranged within the casing at a short distance below the cover and removably supported upon a ledge or shoulder e, formed on the inner side of the casing. This diaphragm receives any dirt which may enter through the gas-escape opening of the cover, thus preventing the same from dropping to the bottom of the manhole.

F is a tube or passage through which any gas is allowed to pass from the portion of the casing below the diaphragm to the portionA thereof above the diaphragm, so as to escape through the opening of the cover. In the construction shown in the drawings this tube extends upwardly from the middle of the diaphragm, and its open lower end coincides with an opening formed in the diaphragm, as shown in Fig. l, while its upper end opens into the portion of the casing above the diaphragm. The tube rises to a sufficient height above the diaphragm ro prevent any dirt which drops upon the diaphragm from overilowing into the tube and falling into the bottom of the manhole. The dirt which accumulates on the diaphragm is removed from time to time by withdrawing the diaphragm from the casing.

gis a check-valve applied to the tube or passage F for checking or preventing the entrance of air into the manhole through said tube, while permitting the escape of gas from the manhole into the atmosphere. This valve preferably consists of a ball of aluminium or other light and non-corrosive material, which is seated loosely in the bore or passage of the tube, the bore being tapered downward and its'smallest diameter being smaller than that of the valve, as shown in the drawings, so as to retain the latter in the tube, While allowing it to rise freely. The pressure of any gas that may accumulate in the manhole from any cause will lift the check-valve and escape into the upper portion of the casing and thence through the opening of the cover, and as soon as the gas has passed out the valve again closes the tube automatically, thus practically excluding the atmosphere from the manhole and avoiding the objections arising from the presence of damp air in the manhole.

I claim as my invention- In a manhole-cover, the combination with a casing having in its top a Ventilating or gasescape opening, of a removable diaphragm the Chamber below the diaphragm, substantiaily as set forth. 1o

Vitness my hand this 26th day of March,

(EI-IAS. F. BINGHAM. Vitnesses:

JNO. J. BONNER, ELLA R. DEAN. 

